1999 Volvo S80 T6 - no heat.

[krmckelvey]

My Volvo does not have heat. Changed the timing belt, water pump, thermostat, and flushed the system. Heater core is good. But it still will not blow hot air only cold and is getting air in the system. Any advise would be helpful.
Thanks

[yuckuJackD]

I suspect the temperature motor and/or some of the other motors shown here as 6; 7; 8 and 9:

Other thought is broken/damaged dampers in the air distributor module, labeled here as 1, 2 and 3:
.

I hope it's just loosen plug for some of the motors - this is the easier and cheaper repair in your case.
Good luck.

p.p. When engine is hot, touch the two pipes going into the passanger compartment (to the heater core) whether they are both hot. This is to ensure the heater core is not clogged. In case one of those pipes is not so hot - replace the heater core or remove it for cleaning (bad, bad repair acting a headache if you're a DIYer)

[retcoastie]

YuckuJackD has an excellent post. However, this is not complete;

p.p. When engine is hot, touch the two pipes going into the passanger compartment (to the heater core) whether they are both hot. This is to ensure the heater core is not clogged. In case one of those pipes is not so hot - replace the heater core or remove it for cleaning (bad, bad repair acting a headache if you're a DIYer)

Checking the hoses and pipes did not find our problem. Both were very hot. After doing all the normal stuff, I accidentally touched the bottom of the heater core on the passenger side. It was cold while the pipes and hoses were hot. I removed the core and found that the plastic wall between the input and output chambers had disintegrated, allowing the hot water to enter and leave without passing through the tubes.

I snagged a life time warranty core for $27 with shipping on Ebay. Problem solved.